A doppelgänger is a person's physical double. Seeing one's own doppelgänger often heralds death or serious illness. Paranormal investigators believe that the doppelgänger is an individual's past or future self. In some traditions, the double has no shadow or reflection.
Here are two seriously creepy horror movies about doppelgängers...
The Broken (2009)
Dream Lover (1986)
There's something undeniably scary about children gone evil wether it's through vampirism (Salem's Lot), radioactivity (The Children Of Ravensback), aliens (Village Of The Damned) or just plain insanity (Devil Times Five, We Need To Talk About Kevin, The Good Son).
The following are my favorite evil kids movies...
The Children Of Ravensback (1980)
Bloody Birthday (1981)
Who Can Kill A Child? (1976)
Animals will always be cute and cuddly, even if they take on monstrous proportions. So they might not be the scariest, but they're definitely the most fun. Zombie dogs, demonic cats, killer morays, giant turtles, hungry bears, angry rabbits, ... It would be difficult to pick a favorite. Anyway, here's a small selection...
Belve Feroci (1984)
The Bermuda Depths (1978)
Night Of The Lepus (1972)
What are your favorite monsters?